1. Field
Example embodiments relate to an electro-optic device and a driving method of an electro-optic device.
2. Description of the Related Art
In general, a liquid crystal display having a transmissive or semi-transmissive reflective liquid crystal panel or an organic EL display having an organic EL display panel including an organic EL element panel is widely used as a display of a television set. Such a display has a demand for fast driving of a pixel circuit in line with the recent trend of higher resolution and three-dimensional image display.
In order to allow an image displayed by a display device to be perceived by a user, a shutter glass including a polarization element, such as liquid crystal, may be used. The shutter glass opens and closes the shutter in synchronization with a timing at which an AMOLED panel changes and displays an image for the left and right eyes during 1 frame (60 Hz), and presents a displayed image only to the appropriate eye.
If the panel is made to emit light in a period in which the opening and closing of the shutters are not complete, two left and right images appear to be mixed. Due to this, the panel is in an off mode in which no image is displayed, during the period in which the opening and closing of the shutters are not complete, and all the pixels of the panel simultaneously emit light after one of the shutters is opened. Accordingly, it is possible to attain display quality without the so-called “3D crosstalk” by which the left-eye and right-eye images do not appear to be mixed at all.
For example, a first conventional electro-optic device may include a light emitting element and a pixel circuit having a pixel voltage sustaining and current control circuit in the pixel area of a pixel. The pixel may be installed at a crossing point of a scan line and a data signal line. The light emitting element is an element which self-emits light depending on an amount of current when current flows.
When LOW voltage is applied to the scan line, a pixel circuit including a PMOSFET is synchronized with the timing at which a pixel switch is turned on, and a capacitor is updated as it is charged with a pixel voltage based on image data from the data signal line. Afterwards, when HIGH voltage is applied to the scan line, the pixel switch is turned OFF and the pixel voltage is maintained. After completing the update of data of all the pixels, when a light emitting switch is turned on by applying LOW voltage to a light emission control line of all the pixels simultaneously, the light emitting element emits light by a current flowing from an anode power line to a cathode power line.
To eliminate the above-mentioned 3D crosstalk, the first conventional electro-optic device rewrites the previous pixel voltage of the panel by conducting linear sequential scanning based on left-eye image data during the non-emission period corresponding to a half period, and causes the pixels to emit light and display the left-eye image after completion of the rewriting of the previous pixel voltage. A pixel voltage based on image data is charged in the data signal line while a predetermined signal is being applied to the scan line sequentially, starting from the first row, and the light emitting switch is turned on by a control signal for turning the light emitting switch on, thereby causing the screen to emit light.
Likewise, the first conventional electro-optic device rewrites a previous pixel voltage on the panel by conducting linear sequential scanning based on right-eye image data during the non-emission period of the next subframe, and causes the pixels to emit light and display the left-eye image after completion of the rewriting of the previous pixel voltage.
In the above example, the previous pixel is updated in a period of nearly a quarter of 1 frame. However, if the screen has higher resolution and larger size, it may be difficult to ensure a sufficient period for updating each pixel with display data.
In another example, a second conventional electro-optic device may include a light emitting element and two pixel circuits having a pixel voltage sustaining and current control circuit in the pixel area of a pixel. The pixel may be surrounded by scan lines, a data signal, and an anode power line at a crossing point of a scan line and a data signal line. The second conventional electro-optic device can sustain left and right pixel voltages, respectively, by means of the two pixel circuits within one pixel.
A display data of a right-eye image can be written on the pixel circuit during the emission and display period of a left-eye image kept at the pixel voltage of the pixel circuit. More specifically, in the second conventional electro-optic device, the pixel voltage is updated by linear sequential driving based on the image data of the current frame, after completion of the emission period of the previous frame. The pixel voltage can be updated based on the image data of the current frame, starting from a second emission period of the previous frame, and a period of time lasting until the completion of a first non-emission period can be allocated to a display data update period.
A period of time consumed only for an emission operation in the electro-optic device is added to the existing data update period during non-emission of the second conventional electro-optic device. Accordingly, the total data update period of the second conventional electro-optic device is substantially twice that of the first electro-optic device. The second electro-optic device can have a significant effect against a lack of the data update period. However, the second conventional electro-optic device having a plurality of pixel circuits installed for each pixel has the problem of low productivity because of a significant increase in the number of circuit elements per pixel, and a bottom emission type AMOLED having no pixel circuit and configured to transmit light from an aperture has the problem of low aperture ratio.